1. Field of the Disclosure
The present disclosure relates in general to mineral recovery wells, and in particular to lockdown rings for retaining wellbore members in a housing.
2. Brief Description of Related Art
Tubing hangers are landed on a shoulder in a wellhead. The shoulder prevents downward movement of the tubing hanger in the wellhead. The weight of the tubing hanger and the tubing hanging from the tubing hanger can prevent upward movement of the tubing hanger under some circumstances. A lockdown ring, however, is required to lock the tubing hanger in place when the tubing hanger is subjected to high pressures. Those high pressures can cause the tubing hanger to move axially upward.
Lockdown rings can be energized by an energizing ring. The energizing ring can have a tapered surface that expands the lockdown ring radially outward into a lockdown groove. The energizing ring can itself be moved axially downward by a seal ring. Once the energizing ring energizes the lockdown ring, the energizing ring stays in place to maintain the radial position of the lockdown ring. The seal ring, which actuated the energizing ring, can remain in position to hold the lockdown ring in place. Unfortunately, the seal may need to be removed from time to time. For example, the seal may need to be replaced. High pressure in the wellbore can cause the tubing hanger or the energizing ring to shift upward when the seal has been removed. The nature of the energizing ring, and the tapered surface on the energizing ring, means that any upward movement of the energizing ring can allow the lockdown ring to move radially inward, thus weakening the lock. Continued pressure, and force from the lockdown ring on the energizing ring, can be sufficient to move the lockdown ring from the set position to an unset position. It is desirable to retain the lockdown ring in the set position in spite of vertical movement of the energizing ring.